JPH05258351A - Optical disc - Google Patents

Abstract

PURPOSE:To prevent defective adhesion of an overcoat layer by forming a secondary primer layer on the part of a 2P resin layer not covered with a recording film and also forming a secondary primer layer between the recording film and the overcoat layer. CONSTITUTION:A glass substrate is coated with a primary primer coating material by means of a spin coater and the coated substrate is dried. A stamper is fixed in a 2P molding machine and coated with UV-curing 2P resin and this resin is spread by pressing with the substrate and cured by irradiation with UV from the substrate side in a nitrogen atmosphere. The glass substrate with formed guide grooves is then exfoliated from the stamper and a substrate for an optical disc is obtd. In this case, defective adhesion of an overcoat layer at the outer and inner edges of the optical disc can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to recording / reproducing,
The present invention relates to an erasable optical disc.

[0002]

2. Description of the Related Art A conventional optical disk has a structure in which a recording film is formed by sputtering or vapor deposition on a substrate having guide grooves for the purpose of guiding a laser beam, and then overcoated by spin coating. Was there.

In particular, in the case of an optical disc using a glass substrate as a substrate, firstly a primer layer containing a silane coupling agent as a main component is provided for adhering the glass and the ultraviolet curable resin, and secondly. In order to form a guide groove, a UV-curable resin is applied on a mold (stamper) provided with unevenness of the guide groove, a primer-treated substrate is placed thereon, and the resin is spread by the substrate. After that, the resin is cured by irradiating ultraviolet rays, and then the guide groove is formed on the glass substrate by peeling the resin, that is, a 2P (Photo Polymerization) method is used to form a 2P resin layer. The recording film layer is provided by sputtering or vapor deposition on the
Overcoat layer using UV curable resin with high coating hardness to prevent scratches and corrosion on recording film, and UV curable resin containing antistatic agent to prevent adhesion of dust due to static electricity Is provided.

[0004]

Various overcoat agents have been developed due to the problems of adhesion and corrosion with recording film layers, the problems of wettability with recording film layers, the problems of surface tension and curing shrinkage, etc. However, the problems of repellency and poor adhesion could not be solved sufficiently, and therefore any of the overcoating agents could not be evenly applied onto the disk, and in high temperature and high humidity (80 ° C, 85% RH). Left for 100 hours,
There is a problem that wrinkles and cracks are generated from a part of the recording film layer corresponding to the overcoat layer portion having poor coatability. Further, there is a problem that various additives used in the overcoating agent in order to solve the wettability and the adhesiveness with the recording film layer may damage the recording film layer, so that a reliable optical disk cannot be provided.

Further, in the conventional structure, that is, the structure in which the primer layer, the 2P resin layer, the recording film layer, and the overcoat layer are sequentially laminated, the portion where the recording film layer is not formed on the 2P resin layer (disc There is an upper inner edge portion and an outer edge portion, and the overcoat agent does not adhere to this portion, so 100 at high temperature and high humidity (80 ° C, 85% RH)
When left for a period of time, there were adverse effects such as wrinkles and cracks in the recording film layer and corrosion of the recording film from the portion where the overcoat layer was not applied.

The problem to be solved by the present invention is the characteristics required for optical discs, in which the overcoating agent can be applied uniformly in appearance, and wrinkles, cracks, and corrosion of the recording film layer do not occur under high temperature and high humidity. , To provide an optical disc having excellent long-term high reliability.

[0007]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventor has laminated a first primer layer, a 2P resin layer, a recording film layer and an overcoat layer on a substrate. In this optical disc, the primer layer is provided at least on the portion of the 2P resin layer where there is no recording film layer before directly providing the overcoat layer on the recording layer, so that the overcoat layer can be formed uniformly on the entire surface of the disc. The present invention has been found and the present invention has been solved.

In other words, in order to solve the above-mentioned problems, the present invention provides an optical disc having a first primer layer, a 2P resin layer, a recording film layer and an overcoat layer sequentially laminated on a substrate, at least on the 2P resin layer. An optical disc provided with a second primer layer in a portion where the recording film layer is absent, and further an optical disc provided with a second primer layer between the recording film layer and the overcoat layer in the optical disc. .

Examples of the substrate used in the present invention include a glass plate or a resin flat plate, on which a photopolymer method (2
The guide groove is formed by the P method).

The first and second primer layers used in the present invention are each formed by applying a primer coating material containing a silane coupling agent and a diluent on a substrate using a coating device such as a spin coater. It

As the silane coupling agent, for example,
γ-methacryloxypropyltrimethoxysilane, β-
(3,4 epoxycyclohexyl) ethyltrimethoxysilane, γ-glyxidoxypropylmethyldiethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ
-Aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane and the like can be mentioned.

As the diluent, for example, ethanol,
Water, toluene, xylene, -n-butyl acetate, cellosolve acetate and the like can be mentioned. These diluents may be used alone or in combination of two or more.

The 2P resin layer of the present invention has the following 2
It is formed by the P method.

That is, on a stamper (molding die formed by transferring from a master by electroforming) having a guide groove for guiding a laser beam and / or an uneven pattern such as preformat signal pits, The glass substrate or the resin substrate is arranged so that the surface on which the first primer layer made of the silane coupling agent is formed is coated with the liquid 2P resin, and the uncured 2P is applied by applying pressure.
By spreading the resin, irradiating ultraviolet light from the substrate side to cure the 2P resin, and peeling it from the stamper,
A 2P resin layer having a desired uneven pattern is formed.

The 2P resin used for forming the 2P resin layer of the present invention includes, for example, a photoradical polymerization composition containing a photoradical polymerizable prepolymer, a monomer and a photoradical polymerization initiator as main components; A cationic photopolymerization composition containing a cationically polymerizable prepolymer, a monomer, and a cationic photopolymerization initiator as main components; a composition obtained by mixing a radical photopolymerization composition and a cationic photopolymerization composition, and the like,
As long as it is a composition that is cured by ultraviolet rays and has good releasability from a stamper after curing, transferability of a concave-convex pattern, and resistance to moist heat, it can be used without particular limitation.

The recording film is usually formed of a dielectric layer, a magneto-optical recording layer and a reflective layer, and if necessary, a second dielectric layer may be formed between the magneto-optical recording layer and the reflective layer. good.

An inorganic dielectric having high transparency is used for the dielectric layer. Examples of the material include SiN _x and Si
O _x , AlSiON, AlSiN, AlN, AlTi
N, Ta ₂ O ₅ , ZnS and the like can be mentioned, but among them, S
iN _x is preferred. The refractive index of these dielectric layers is 1.8 to
A range of 2.5 is preferred.

The dielectric layer is formed by physical vapor deposition (PVD) such as sputtering or ion plating, or plasma CV.
It is formed by a chemical vapor deposition method (CVD) such as D.

Examples of the material forming the magneto-optical recording layer are TbFeCo, DyFeCo, TbFe and GdT.
Examples thereof include bFeCo, NdDyFeCo, and TbCo, and those obtained by adding other metals to these amorphous alloys for the purpose of improving oxidation resistance can also be used.

As the sputtering conditions for forming the magneto-optical recording layer, the sputtering gas pressure is changed. in this case,
Although the same target is used, the film formation rate varies depending on the sputtering gas pressure. Therefore, in order to control the film thickness, the film formation rate is obtained in advance and the sputtering time at each gas pressure is determined.

Examples of the material of the reflective layer include Al and alloys of Al and other metals. Al, Al-Ti alloys and Al-Cr alloys are preferable.

The reflective layer is formed by physical vapor deposition (PVD) such as sputtering or ion plating, or plasma CVD.
It is formed by a chemical vapor deposition method (CVD) or the like.

When forming the overcoat layer, methods such as a dipping method, a spin coating method, a roll coater method and a vapor deposition method are used. Among these protective coating methods, the spin coating method using an ultraviolet curable resin is preferable because it is a simple and quick method. In this method, an ultraviolet curable resin is discharged onto a substrate using a dispenser, a disk is rotated at a high speed, and the resin is spread by centrifugal force to apply the resin. The applied resin is then cured by UV irradiation. The spin coating method can also be suitably used for resins other than the ultraviolet curable resin. In any case, the resin used for the protective coat layer preferably has a pencil hardness of H or higher after curing.

The magneto-optical recording medium thus formed may be used alone or may be used by adhering two so that the substrates are on the outside.

[0025]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 A first primer coating composition having the following composition was applied on a glass substrate using a spin coater and then dried. Next, the stamper was fixed to a 2P molding machine, a UV curable 2P resin (“STN-402” manufactured by Dainippon Ink and Chemicals, Inc.) was applied on the stamper, and the glass substrate was treated with the first primer. The 2P resin was spread with and was irradiated with ultraviolet rays from the glass substrate side in a nitrogen atmosphere to cure the 2P resin. Then, the glass substrate on which the guide groove was formed was peeled from the stamper to obtain an optical disc substrate.

On the obtained optical disk substrate, a SiN film of 1,000 angstroms was formed by a sputtering method.
TbFeCo film 300 Å, SiN film 30
A recording film consisting of a four-layer film of 0 Å and an Al film of 500 Å was formed.

A second primer having the following composition was uniformly applied to the entire surface of the disk on the substrate thus formed by using a spin coater, and the second primer was baked. After that, an ultraviolet-curable overcoat agent (“SD-301” manufactured by Dainippon Ink and Chemicals, Inc.) was applied, and the overcoat agent was cured by irradiation with ultraviolet rays to obtain an optical disk as shown in FIG. .

The obtained optical disk was free from coating unevenness and repellency caused by surface tension and curing shrinkage that occur when the overcoat agent is applied. Moreover, as a result of leaving the obtained optical disc in high temperature and high humidity (80 ° C., 85% RH) for 1,000 hours, no wrinkles, cracks, etc. were generated and no influence on the recording film was observed.

(First primer) (1) γ-methacryloxypropyltrimethoxysilane 15 parts by weight (2) ethanol 85 parts by weight

(Second primer) (1) γ-aminopropyltriethoxysilane 20 parts by weight (2) Toluene 80 parts by weight

(Embodiment 2) A glass substrate on which guide grooves are formed and a recording film is formed is used in the same manner as in Embodiment 1, and the boundary between the recording film layer and the 2P resin layer on the inner and outer peripheral portions and The second primer paint was applied on the 2P resin layer on which the recording film was not formed. After that, overcoating was performed in the same manner as in Example 1 to obtain an optical disc as shown in FIG.

The obtained optical disk was free from coating spots and repelling as in Example 1, and was exposed to high temperature and high humidity (80 ° C., 85 ° C.).
% RH) for 1,000 hours, no wrinkles, cracks or the like were observed and no influence on the recording film was observed.

Comparative Example 1 A glass substrate on which a guide groove was formed and a recording film was formed in the same manner as in Example 1 was directly overcoated in the same manner as in Example 1, and An optical disc as shown in was obtained.

The obtained optical disc was repelled from the inner peripheral portion and the outer peripheral portion where the recording film layer was not formed due to the surface tension of the overcoat agent and the curing shrinkage during ultraviolet curing. Further, when this optical disk was left in high temperature and high humidity (80 ° C., 85% RH) for 100 hours, wrinkles and cracks were generated from the portion not overcoated.

[0036]

INDUSTRIAL APPLICABILITY The optical disc of the present invention prevents adhesion defects of the overcoat layer at the outer edge portion and inner edge portion of the optical disc, and does not cause wrinkles, cracks, corrosion or the like on the recording film layer, and therefore has high long-term reliability. It is an excellent one.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a layer structure of an optical disc of the present invention.

FIG. 2 is a schematic cross-sectional view showing the layer structure of the optical disc of the present invention.

FIG. 3 is a schematic cross-sectional view showing a layer structure of a conventional optical disc.

[Explanation of symbols]

 1 Glass Substrate 2 First Primer Layer 3 2P Resin Layer 4 Recording Film Layer 5 Second Primer Layer 6 Overcoat Layer

Claims (2)

[Claims] 1. An optical disk comprising a substrate, on which a first primer layer, a 2P resin layer, a recording film layer and an overcoat layer are sequentially laminated, at least a second film is formed on a portion of the 2P resin layer where there is no recording film layer. An optical disc having a primer layer. 2. The optical disc according to claim 1, further comprising a second primer layer between the recording film layer and the overcoat layer.